Very large two piece tires, in which a removable tread belt is mounted upon a pneumatic structure, have been designed for use on large earthmover vehicles. The large two piece tires are subjected to high stress and loads under harsh environmental conditions such as in rock quarries, mines, foundries, and other areas where tires are subjected to puncture-producing and wear-inducing conditions.
Two engineering challenges separate the two piece tires from standard one-piece tires. The first engineering challenge is to retain the outer tread belt on the casing, which requires enough interfacial pressure between the tread belt and carcass. The second engineering challenge is to ensure that the tread has adequate circumferential stiffness to restrain the diametric growth of the casing. The tread ring must also have enough flexural compliance to have a nonzero interfacial pressure at the leading and trailing edges of the footprint, and low circumferential compliance to compress the belt package in the footprint in the circumferential direction. These opposing requirements make it difficult to design a two piece tire which is utilized under heavy load conditions.
With the continual drive to improve earthmover performance, there is a continuing need to provide novel methods and tire designs for improving earthmover tire durability. The present invention is directed to an improved pneumatic tire and removable tread belt assembly with which the frequency of premature tire failure is thought to be substantially reduced. The present invention is also directed to providing an improved pneumatic tire and tread belt assembly which is designed to allow large tires to be transported in several sections and then assembled at the construction site to ease the otherwise difficult problem of transporting the large tires, i.e. sometimes over 13 feet in height and approximately 8,000 to 15,000 pounds. Moreover, the present invention relates to an improved pneumatic tire and removable tread belt assembly with which the driving characteristics of the tire can be more economically changed and the inventory of the number of tire spares that are typically needed can be reduced.